Answer by Willian Z for Can you set passwords in .ssh/config to allow automatic login?

If you don't have direct access to key-pair, you could encrypt password on your local machine.

The way to do it is encrypt your password using key in addition to @Eric Woodruff 's ProxyCommand.

A way to combine is using pipe:

openssl rsautl -decrypt -inkey /path/to/decrypt_key -in /path/to/encrypted_password  | sshpass ssh real-destination -tt

where

Host real-destination    Hostname test.com    User netmoon